1. Field of the Invention
This invention relates to a portable generator, and more particularly to a portable generator having the function of automatically adapting itself to parallel operation of a plurality of portable generators including the first-mentioned portable generator connected in parallel with each other by automatically synchronizing the phases of outputs from the generators.
2. Prior Art
When a plurality of portable generators connected in parallel with each other are in operation, if the output voltages from the generators are not synchronous, there occurs a difference between the output voltages. This causes electric current to flow from one generator into another generator, which can result in such an excessive amount of electric current flowing in the one generator as may destroy component parts thereof. Therefore, it is required to synchronize the output voltages from the generators.
To this end, even in the case of parallel operation of identically-constructed portable generators, it is required to provide wiring for transmitting signals for informing each other of operating conditions thereof. Further, as disclosed e.g. in Japanese Patent Publication (Kokoku) No. 56-20782, it is required to employ an automatic synchronizing device and means for producing an operating point at which the phases coincide with each other in order to cause the automatic synchronizing device to operate promptly and reliably. Alternatively, as disclosed in Japanese Provisional Utility Model Publication (Kokai) No. 62-145440, a special adaptor has to be used for parallel operation of two portable generators, with one of them serving as a master generator while the other serves as a slave generator.